In contrast to a mechanical water pump driven by engine power, an electric water pump may be independently controlled by a motor.
Because an electric water pump may drive cooling water according to operating conditions of an engine and a vehicle independently of the operation of the engine, an electric water pump may provide several advantages.
First, an engine warm-up time period may be shortened by stopping circulation of the cooling water through the electric pump at initial startup. Second, power consumption may be reduced compared to the mechanical water pump by 60˜70% flow rate control. Third, motor driving, not belt driving, is favorable in view of layout.
At the same time, a BLDC motor is applied as a DC motor that is used for rotation of an impeller which pumps the cooling water, and a controller which controls the BLDC motor is built into the motor.
Since the controller has high device density due to integration of the circuit, and is positioned within a small space due to a limited size of the motor for mounting the motor to the engine, the controller may include the board on which a circuit may be printed and devices attached to the board.
Regarding the boards, there are FR4 (a resin group) boards and ceramic boards, where a ceramic board is preferable at high temperature and enables high density integration using various techniques, such as a printing circuit technique, and has excellent high-temperature characteristics.
Furthermore, because the ceramic board has one side with the circuit printed thereon and the other side which may be insulated and require cooling, the ceramic board may be attached to a partition wall which divides the controller chamber from the motor chamber or a separate mounting case.
In this instance, despite the merits of the ceramic, one reason why the ceramic board is attached thus is because of the difficulty in securing the ceramic board using a bolt or a nut due to its high brittleness, and its vulnerability to impact. Thus, a ceramic board is susceptible to breakage both in driving and handling, and assembly of the ceramic board may be difficult even when the ceramic board is attached to the electric water pump.
The above information disclosed in this Background section is only for the enhancement of the understanding of the background of the inventive concept and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.